How to modify array element within javascript object?

Question

I am writing my code in NodeJS and have a object which looks as below.

const jsonData=
{
    "description": "description",
    "hosts": [
        "host1",
        "host2",
        "host3"
    ]
}

I want to delete all host elements execpt the first one.

Desired Output:

const jsonData=
{
    "description": "description",
    "hosts": [
        "host1"
    ]
}

And, the remaining elements should be moved to another variable.

const hostelementsExceptFirst = [ "host2", "host3" ];

I am performing the following operation but it is not giving desired output.

delete jsonData['hosts'];

There's no such thing as a "JSON Object"

Phil
– Phil

2021-07-15 23:15:47 +00:00
Commented Jul 15, 2021 at 23:15 — Phil
– Phil, Commented Jul 15, 2021 at 23:15

Keith · Accepted Answer · 2021-07-15 23:20:28Z

4

If you just want to mutate the array, you can use splice..

eg..

const jsonData =
{
    "description": "description",
    "hosts": [
        "host1", "host2", "host3"
    ]
}

const hostelementsExceptFirst = jsonData.hosts.splice(1);

console.log(jsonData);
console.log(hostelementsExceptFirst);

answered Jul 15, 2021 at 23:20

Keith

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Comments

gunwin · Accepted Answer · 2021-07-15 23:16:44Z

2

You can use Array.slice() to take a section of an array, and just reassign the hosts value afterwards.

const jsonData =
{
    "description": "description",
    "hosts": [
        "host1", "host2", "host3"
    ]
}

const remainers = jsonData.hosts.slice(1);
jsonData.hosts = [jsonData.hosts[0]];

console.log(jsonData);
console.log(remainers);

answered Jul 15, 2021 at 23:16

gunwin

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Comments

Anton Neverov · Accepted Answer · 2021-07-15 23:15:41Z

1

const [firstValue, ...othersValues] = jsonData.hosts;

firstValue will be host1, and othersValues will be array with others

answered Jul 15, 2021 at 23:15

Anton Neverov

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1 Comment

Phil Over a year ago

This is a good start but doesn't alter the jsonData.hosts at all

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